Created by: Glen Zhu | Updated Date: March 3rd, 2025
In circuit diagram, you may find the symbol below.Actually it is the symbol of a surge protective device.And we can take “SPD”for short.A 2023 report by the National Fire Protection Association (NFPA) revealed that 23% of electronic device failures in U.S. households were surge-related, and the average repair costs surpassing $1,200 per incident.
SPD are misunderstood as simple power strips, which ignore the truth that SPD can do more than that. SPD are warriors fighting against the peak voltage. This article will show more details of SPD and find the final truth: what does a surge protective device protect against.
Firstly, let’s talk about the operational principle of SPD. The operational principle of a surge protector (SPD) is to limit or divert transient overvoltages through different components and mechanisms,so as to protect against obliterate equipment. Below are some common operational principles of SPD:
Metal Oxide Varistor (MOV)
Silicon Avalanche Diode (SAD)
The operational principle of SPD is mainly realized by using its internal nonlinear components.And the components have high impact resistance and long service life, which means they can effectively suppress surge voltage and lightning impact.
Secondly，having understood the working principle of SPD, we gonna know their three levels according to different usage needs.
2. B-level SPD (B band):It is mainly used to protect commercial equipment from surges, such as computers and various instruments etc. Its rated discharge current is 10KA, suitable for circuits with voltages of 22V and 380V, which mainly limit and eliminate high-frequency surge overvoltage up to 10kHz in power lines.
Above we can find three levels are almost cover the voltage in companies, government and families.
Thirdly, due to different SPDs to be selected in different application scenarios,we can find what do the Surge Protective Device protect against accordingly.
Enterprise Servers and Data Centers: A voltage spike can damage financial storage records, medical databases, or cloud-based information. Hierarchical surge protection system in data centers ensure 99.999% uptime**, critical for industries like healthcare and finance.
Personal Devices: Laptops, external hard drives, and NAS (Network Attached Storage) systems, storing up a large amount of housing family photos, work documents, or creative projects are shielded. SPD could protect against decades of data loss.
LoT Ecosystems: Smart home devices ( security cameras, thermostats, voice assistants etc) rely on uninterrupted connectivity. SPD can protect against firmware corruption, resulting in expensive reset or replacement.
In 2022, a lightning-caused surge at a Texas hospital corrupted patient records, which delayed treatments and resulting in $2.3 million in recovery costs. This can be avoided with proper surge protection.
According to industry reports, surge protectors save significant costs for American users by extending equipment life and reducing maintenance expenses. For example, ECS offers a replacement commitment for up to 15-25 years, reducing long-term usage costs. The economic benefits are particularly obvious in high-risk fields as power, communication, and medical.
In conclusion, SPD are not mere accessories but also essential infrastructure, covering fields from household appliances to industry. They protect tangible assets (devices, buildings), intangible value (data, productivity,time), and human lives. As society’s reliance on electronic products,installing SPD becomes a responsibility. Whether for a smart home, a hospital, or the government, the question is no longer to install surge protectors or not, but how comprehensive their coverage must be to match the scale of modern electrical dependencies.
Surge protector and lighting arrester are protective devices that are immune to over-voltage. But they still have difference in some respects.
Lightning Arrester
The rate voltage of surge lighting arrester: <3kv to 1000kv, low voltage 0.28kv,0.5kv.
The rate voltage of surge protector: 1.2kv, 380,220~10v~5v.
Lighting arrester can directly protect electric apparatus, and surge protector is generally a secondary protection to single circuit or power supplier to terminal electronic instruments and meters.
As the objects of protection are different, the level of voltage resistance is different accordingly. The residual voltage of the over-voltage protection device should match the level of withstand pressure of the object of protection
The arrester is generally installed on the primary system to prevent the direct intrusion of lightning waves and protect overhead lines and electrical equipment.
LSP’s reliable surge protection devices (SPDs) are designed to meet the protection needs of installations against lightning and surges. Contact our Experts!
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